Multi-Clutch Transmission Central Synchronizing Unit
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Solution Overview
Problem
Dual clutch transmissions face challenges in achieving compact, powerful, cost-efficient, and low-power-loss synchronizing means, especially in heavy on- and off-road vehicles, due to the complexity and cost of existing synchronizing devices like hydraulic pumps, electric motors, and multiple synchronizing clutches.
Innovation Solution
A central synchronizing unit with an axially movable synchronizing member featuring internal and external conical friction surfaces, where the synchronizing member is rotationally locked to the countershaft and actuated via a control rod, allowing for efficient speed ratio adjustments between input and output shafts without the need for additional gearwheels or complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pumps and valves are used for synchronizing gearwheels, then synchronizing capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex hydraulic synchronization systems with a purely mechanical synchronization mechanism. The synchronization is achieved through direct mechanical engagement of gearwheels with the input shaft, using centrifugal forces and friction surfaces to match rotational speeds without requiring hydraulic pumps, valves, or fluid pressure systems.
Solution Approach 2:
The synchronization mechanism uses the rotational motion and centrifugal forces naturally generated by the gearwheels themselves to achieve speed matching. The system self-regulates synchronization through the interaction of friction surfaces and centrifugal weights, eliminating the need for external hydraulic control systems.
2Reliability
If electric motors are used for synchronizing sub-transmissions, then synchronizing capability is improved, but weight and cost increase
Solution Approach 1:
The patent eliminates electric motors and their associated drive mechanisms by using a passive mechanical synchronization system. The gearwheels are directly coupled to the input shaft through friction surfaces that automatically equalize rotational speeds through contact friction, without requiring external power sources or electromagnetic actuators.
Solution Approach 2:
The invention extracts and removes the electric motor component from the synchronization system, retaining only the essential mechanical elements (friction surfaces, centrifugal weights, and gearwheel engagement mechanisms) that can achieve synchronization through the vehicle's existing power flow.
3Reliability
If multiple synchronizing clutches are used, then synchronizing capability is improved, but power losses increase
Solution Approach 1:
The patent merges the synchronization function with the existing gearwheel engagement mechanism, eliminating the need for separate synchronizing clutches. The same friction surfaces and engagement interfaces used for gearwheel-to-input-shaft connection also perform the synchronization function, reducing the total number of friction interfaces and associated power losses.
4Ease of manufacture
If conventional stepped transmission design is used, then manufacturing cost is reduced, but power interruption occurs at gear shifts
Solution Approach 1:
The patent segments the transmission system into multiple gearwheel sets that can be independently engaged with the input shaft. This allows one gearwheel to be pre-selected while another is actively transmitting power, enabling seamless switching between gears without interrupting the power flow to the output shaft.
Solution Approach 2:
The system pre-selects the next gearwheel to be engaged while the current gear is still transmitting power. The gearwheels are positioned and synchronized in advance, so that when the clutch switches, the pre-positioned gearwheel is already at the correct speed and position for immediate engagement, eliminating shift interruptions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a compact, powerful, and cost-effective synchronizing mechanism with reduced power losses, as it utilizes overlapping conical surfaces to synchronize gearwheels, minimizing axial space and maintaining performance while reducing the number of friction surfaces and control complexity.
Implementation Method 1
said synchronizing member comprises an internal and an external conical friction surface that are axially overlapping each other
Data Source
AI summary
A multi-clutch transmission for a motor vehicle is provided where a central synchronizing unit includes an axially movable synchronizing member that is arranged on and rotationally locked with a countershaft. In actuated states of the central synchronizing unit, the synchronizing member is displaced axially into engagement with mating portions of two gearwheels that are rotatably arranged on the countershaft. The synchronizing member includes an internal and an external cortical friction surface that axially overlap each other, and the mating portions on the two of the gearwheels are mating conical surfaces.